Schiff base type compound and coloring material containing the same

ABSTRACT

Disclosed are a compound that emits fluorescence, particularly in its solid state, and is suited to provide a color converting material with various improved performance properties over prior art and a light emitter, a color conversion filter, a color conversion device, and a photoelectric device each containing the compound; particularly a Schiff base type compound of formula (I) and a coloring material, a color conversion layer, a light absorbing layer, a color conversion filter, a light absorbing filter, a color-converting light-emitting device, and a photoelectric device each containing the compound. 
                         
The definition of the symbols in formula (I) is the same as in the specification.

TECHNICAL FIELD

This invention generally relates to a novel Schiff base type compound.The invention also relates to a coloring material, a color conversionlayer, a light absorbing layer, a color conversion filter, a lightabsorbing filter, a color converting light emitting device, and aphotoelectric device each containing the Schiff base type compound. Moreparticularly, it relates to a color conversion filter useful inapplications to: display devices, such as liquid crystal displays, PDPs,and organic electro luminescent displays; display panels of imagesensors, personal computers, word processors, audio equipment, videoequipment, car navigation systems, phones, personal digital assistants,and industrial instruments; lighting equipment, such as fluorescentlamps, LEDs, and EL lamps; colorant lasers; copy protect systems; andphotoelectric devices, such as solar cells. The invention also relatesto an optical filter (color conversion filter) that allows formulticolor display with high definition, high brightness, highefficiency, and good productivity.

BACKGROUND ART

Materials that absorb energy to excite electrons and emitelectromagnetic radiation as extra energy when the excited electronsreturn to the ground state exhibit wavelength conversion performance andhave been used as a color (or wavelength) converting colorant in dye orpigment formulations, optical filters, and agricultural filters. Inparticular, organic compounds of such materials have been studiedextensively because they have more easily controllable absorption andemission wavelengths than inorganic compounds. Among them, compoundsthat emit absorbed energy as fluorescence are called fluorescentcolorants. Of the fluorescent colorants those emitting visiblefluorescence are of high utility and have found application in displays,lighting equipment, such as fluorescent lamps, biological or medicalmarkers, and so on.

Schiff base type compounds have been used in the form of their metalcomplexes as an optical recording material or an optical filter materialas disclosed in patent documents 1 to 3 (see below).Fluorescence-emitting colorants are applicable to a high brightness,high efficiency color conversion filter. Inter alia, those emittingfluorescence in their solid state have been awaited in view of highpractical utility. For example, patent documents 4 to 7 (see below)disclose compounds that emit fluorescence in their solid state. However,the colorants disclosed in the literature are not quite sufficient interms of various performance requirements.

-   Patent document 1: JP 2004-034645A-   Patent document 2: JP 2004-345212A-   Patent document 3: JP 2007-210890A-   Patent document 4: WO 2004/072053-   Patent document 5: WO 2005/078024-   Patent document 6: JP 2005-255992A-   Patent document 7: JP 2008-195749

SUMMARY OF INVENTION Problem to be Solved by the Invention

An object of the invention is to provide a novel compound that emitsfluorescence, particularly in a solid state, and is suited for use as acolor converting material showing improvements in various performanceproperties over prior art. Another object of the invention is to providea light emitter, a color conversion filter, a color conversion device,and a photoelectric device each containing the novel compound.

Means for Solving the Problem

As a result of extensive studies, the present inventors have found thata Schiff base type compound having a specific structure has a highfluorescence intensity and emits fluorescence in its solid state. Theabove objects of the invention are accomplished by use of the Schiffbase type compound.

Based on the above finding, the invention provides a novel Schiff basetype compound represented by general formula (I):

wherein ring A represents an aromatic ring, an aliphatic ring, or aheterocyclic ring; Ar represents a 5- or 6-membered heterocyclic oraromatic ring; and X represents a halogen atom, the aliphatic ringrepresented by ring A and the aromatic ring and the heterocyclic ringrepresented by ring A or Ar being optionally fused to a ring oroptionally substituted.

The invention also provides a coloring material containing at least oneSchiff base type compound of the invention.

The invention also provides a color conversion layer containing thecoloring material of the invention.

The invention also provides a light absorbing layer containing thecoloring material of the invention.

The invention also provides a color conversion filter including one ormore color conversion layers at least one of which is the colorconversion layer of the invention.

The invention also provides a light absorbing filter including one ormore light absorbing layers at least one of which is the light absorbinglayer of the invention.

The invention also provides a color-converting light-emitting deviceincluding a light emitting portion and one of the color conversion layerand the color conversion filter of the invention.

The invention also provides a photoelectric device including aphotoelectric element and the color conversion filter of the invention.

Effect of the Invention

Having the above described structure, the invention provides a novelSchiff base type compound that emits fluorescence in its solid statesuitable for use. Using a color conversion layer made of a coloringmaterial containing the Schiff base type compound of the inventionprovides a color conversion filter, a color-converting light-emittingdevice, and a photoelectric device that achieve high brightness and highcolor conversion efficiency. Using a light absorbing layer made of thecoloring material of the invention provides a light absorbing filteraffording high color purity.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1( a), FIG. 1( b), and FIG. 1( c) are each a schematiccross-section of a preferred embodiment of a light absorbing filteraccording to the invention.

FIG. 2 is a schematic cross-section of a preferred embodiment of acolor-converting light-emitting device according to the invention.

FIG. 3 is a schematic cross-section of a preferred embodiment of aphotoelectric device according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The Schiff base type compound of the invention and the coloringmaterial, color conversion layer, light absorbing layer, colorconversion filter, color-converting light-emitting device, andphotoelectric device using the Schiff base type compound will bedescribed in detail based on their preferred embodiments.

The Schiff base type compound of the invention is a compound representedby general formula (I) above and is characterized by having a 6-memberedring formed by the coordination of a boron atom and a nitrogen atom. Itis excellent in fluorescence intensity and able to emit fluorescence inits solid state.

Examples of the aromatic ring represented by ring A and Ar in generalformula (I) include benzene ring, naphthalene ring, anthracene ring,phenanthrene ring, pyrene ring, biphenyl ring, p-terphenyl ring, andm-terphenyl ring.

Examples of the aliphatic ring represented by ring A in general formula(I) include cyclopentane ring, cyclohexane ring, cycloheptane ring, andcyclooctane ring.

Examples of the heterocyclic ring represented by ring A and Ar ingeneral formula (I) include pyrrole ring, thiophene ring, furan ring,pyran ring, thiopyran ring, imidazole ring, pyrazole ring, thiazolering, isothiazole ring, oxazole ring, isoxazole ring, pyridine ring,pyrazine ring, pyrimidine ring, pyridazine ring, pyrrolidine ring,pyrazolidine ring, imidazolidine ring, isoxazolidine ring,isothiazolidine ring, piperidine ring, piperazine ring, morpholine ring,thiomorpholine ring, chromane ring, thiochromane ring, isochromane ring,isothiochromane ring, indoline ring, isoindoline ring, pyrindine ring,indolizine ring, indole ring, indazole ring, purine ring, quinolidinering, isoquinoline ring, quinoline ring, naphthyridine ring, phthalazinering, quinoxaline ring, quinazoline ring, cinnoline ring, pteridinering, acridine ring, perimidine ring, phenanthroline ring, carbazolering, carboline ring, phenazine ring, anthyridine ring, thiadiazolering, oxadiazole ring, triazine ring, triazole ring, tetrazole ring,benzimidazole ring, benzoxazole ring, benzothiazole ring,benzothiadiazole ring, benzofuroxan ring, naphthoimidazole ring,benzotriazoles ring, and tetraazaindene ring.

Examples of the halogen atom represented by X in general formula (I)include fluorine, chloride, bromine, and iodine.

The aromatic ring and the heterocyclic ring represented by ring A and Arand the aliphatic ring represented by ring A in general formula (I) maybe substituted. Substituents include alkyl groups, such as methyl,ethyl, propyl, isopropyl, cyclopropyl, butyl, sec-butyl, tert-butyl,isobutyl, amyl, isoamyl, tert-amyl, cyclopentyl, hexyl, 2-hexyl,3-hexyl, cyclohexyl, bicyclohexyl, 1-methylcyclohexyl, heptyl, 2-heptyl,3-heptyl, isoheptyl, tert-heptyl, n-octyl, isooctyl, tert-octyl,2-ethylhexyl, nonyl, isononyl, and decyl; alkoxy groups, such asmethyloxy, ethyloxy, propyloxy, isopropyloxy, butyloxy, sec-butyloxy,tert-butyloxy, isobutyloxy, amyloxy, isoamyloxy, tert-amyloxy, hexyloxy,cyclohexyloxy, heptyloxy, isoheptyloxy, tert-heptyloxy, n-octyloxy,isooctyloxy, tert-octyloxy, 2-ethylhexyloxy, nonyloxy, and decyloxy;alkylthio groups, such as methylthio, ethylthio, propylthio,isopropylthio, butylthio, sec-butylthio, tert-butylthio, isobutylthio,amylthio, isoamylthio, tert-amylthio, hexylthio, cyclohexylthio,heptylthio, isoheptylthio, tert-heptylthio, n-octylthio, isooctylthio,tert-octylthio, and 2-ethylhexylthio; alkenyl groups, such as vinyl,1-methylethenyl, 2-methylethenyl, 2-propenyl, 1-methyl-3-propenyl,3-butenyl, 1-methyl-3-butenyl, isobutenyl, 3-pentenyl, 4-hexenyl,cyclohexenyl, bicyclohexenyl, heptenyl, octenyl, decenyl, pentadecenyl,eicosenyl, and tricosenyl; arylalkyl groups, such as benzyl, phenethyl,diphenylmethyl, triphenylmethyl, styryl, and cinnamyl; aryl groups, suchas phenyl and naphthyl; aryloxy groups, such as phenoxy and naphthyloxy;arylthio groups, such as phenylthio and naphthylthio; heterocyclicgroups, such as pyridyl, pyrimidyl, pyridazyl, piperidyl, pyranyl,pyrazolyl, triazyl, pyrrolyl, quinolyl, isoquinolyl, imidazolyl,benzimidazolyl, triazolyl, furyl, furanyl, benzofuranyl, thienyl,thiophenyl, benzothiophenyl, thiadiazolyl, thiazolyl, benzothiazolyl,oxazolyl, benzoxazolyl, isothiazolyl, isoxazolyl, indolyl,2-pyrrolidinon-1-yl, 2-piperidon-1-yl, 2,4-dioxyimidazolidin-3-yl, and2,4-dioxyoxazolidin-3-yl; halogen atoms, such as fluorine, chlorine,bromine, and iodine; acyl groups, such as acetyl, 2-chloroacetyl,propionyl, octanoyl, acryloyl, methacryloyl, phenylcarbonyl (i.e.,benzoyl), phthaloyl, 4-trifluoromethylbenzoyl, pivaloyl, salicyloyl,oxaloyl, stearoyl, methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl,n-octadecyloxycarbonyl, and carbamoyl; acyloxy groups, such as acetyloxyand benzoyloxy; an amino group; substituted amino groups, such asethylamino, dimethylamino, diethylamino, butylamino, cyclopentylamino,2-ethylhexylamino, dodecylamino, anilino, chlorophenylamino, toluidino,anisidino, N-methylanilino, diphenylamino, naphthylamino,2-pyridylamino, methoxycarbonylamino, phenoxycarbonylamino, acetylamino,benzoylamino, formylamino, pivaloylamino, lauroylamino, carbamoylamino,N,N-dimethylaminocarbonylamino, N,N-diethylaminocarbonylamino,morpholinocarbonylamino, methoxycarbonylamino, ethoxycarbonylamino,t-butoxycarbonylamino, n-octadecyloxycarbonylamino,N-methylmethoxycarbonylamino, phenoxycarbonylamino, sulfamoylamino,N,N-dimethylaminosulfonylamino, methylsulfonylamino, butylsulfonylamino,and phenylsulfonylamino; sulfonamido, sulfonyl, carboxyl, cyano, sulfo,hydroxyl, nitro, mercapto, imido, carbamoyl, and sulfonamido. Thesesubstituents may be substituted. The substituted amino group, thecarboxyl group, and the sulfo group may be in the form of a salt.

Of the Schiff base type compounds of general formula (I) thoserepresented by general formula (II) shown below, particularly thoserepresented by general formula (III) shown below are preferred; for theyare prepared from easily available materials and exhibit more suitablefluorescence characteristics for use as a fluorescent material.

Of the Schiff base type compounds described, the following compounds aremore preferred for their excellent fluorescence characteristics.

Compounds of general formula (II) or (III) in which R¹, R², R³, and R⁴are each hydrogen, optionally substituted C1-C10 alkyl, or —NRR′(wherein R and R′ are each C1-C10 alkyl and may be taken together withthe adjacent R¹, R², R³, or R⁴ to form a ring structure) and/or Ar is aoptionally substituted C6-C30 aromatic ring or a optionally substitutedC3-C20 heterocyclic ring. The substituent on the aromatic or theheterocyclic ring represented by Ar is preferably selected from halogen,halogen-substituted C1-C5 alkyl, and/or —NRR′ (wherein R and R′ are eachC1-C10 alkyl or C6-C10 aryl).

In particularly, compounds of general formula (II) or (III) in which R¹,R², R³, and R⁴ are each hydrogen, optionally substituted C1-C5 alkyl, or—NRR′ (wherein R and R′ are each C1-C5 alkyl and may be taken togetherwith the adjacent R¹, R², R³, or R⁴ to form a ring structure) and/or Aris a optionally substituted C6-C20 aromatic ring or a optionallysubstituted C3-C15 heterocyclic ring. The substituent on the aromatic orthe heterocyclic ring represented by Ar is preferably halogen,halogen-substituted C1-C15 alkyl, and/or —NRR′ (wherein R and R′ areeach C1-C5 alkyl or C6-C10 aryl).

Of the Schiff base type compounds described, the following compounds arealso more preferred for their excellent light resistance.

Compounds of general formula (I) in which at least one of the hydrogenatoms bonded to ring A or Ar is displaced by an amino group representedby —NRR′ (wherein R and R′ each represent C1-C10 alkyl or C6-C10 aryland may be each taken together with ring A or Ar to form a ringstructure).

Compounds of general formula (II) or (III) in which at least one of thehydrogen atoms possessed by Ar, or R¹, R², R³, or R⁴ is displaced by anamino group represented by —NRR′ (wherein R and R′ each represent C1-C10alkyl or C6-C10 aryl and may be each taken together with ring A or Ar toform a ring structure).

wherein R¹, R², R³, and R⁴ each independently represent a hydrogen atom,a halogen atom, a nitro group, a cyano group, a hydroxyl group, acarboxyl group, —NRR′, an optionally substituted alkyl group having 1 to20 carbon atoms, an optionally substituted aryl group having 6 to 20carbon atoms, an optionally substituted heterocyclic ring having 4 to 20carbon atoms, or an optionally substituted arylalkyl group having 7 to20 carbon atoms; or adjacent two of R¹, R², R³, and R⁴ are takentogether to form an aliphatic, aromatic, or heterocyclic ring, themethylene chain of the alkyl group or the arylalkyl group and the bondbetween the aryl group and the benzene ring being optionally interruptedby —O—, —S—, —SO₂—, —CO—, —OCO—, or —COO—; and R and R′ each representan alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to20 carbon atoms; or R and R′ are taken together with the adjacent R¹,R², R³, or R⁴ to form a ring structure, the aromatic ring formed by theconnection of adjacent two of R¹, R², R³, and R⁴ being optionally fusedto a ring or substituted; Ar and X are as defined for general formula(I).

wherein Ar is as defined for general formula (I); and R¹, R², R³, and R⁴are as defined for general formula (II).

The optionally substituted alkyl group having 1 to 20 carbon atomsrepresented by R¹, R², R³, and R⁴ in general formulae (II) and (III) maybe straight chain, branched, or cyclic. Examples thereof include methyl,ethyl, propyl, isopropyl, butyl, s-butyl, t-butyl, isobutyl, amyl,isoamyl, t-amyl, hexyl, heptyl, isoheptyl, t-heptyl, n-octyl, isooctyl,t-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-dodecyl, n-tridecyl,n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,cyclooctyl, cyclononyl, and cyclodecyl. Examples of the alkyl group themethylene chain of which is interrupted by —O— include methoxy, ethoxy,propyloxy, isopropyloxy, methoxymethyl, ethoxymethyl, and2-methoxyethyl. Examples of the alkyl group the methylene chain of whichis interrupted by —S— include methylthio, ethylthio, butylthio, andpentylthio. Examples of the alkyl group the methylene chain of which isinterrupted by —SO₂— include methylsulfonyl, ethylsulfonyl,butylsulfonyl, and pentylsulfonyl. Examples of the alkyl group themethylene chain of which is interrupted by —CO— include acetyl,1-carbonylethyl, acetylmethyl, 1-carbonylpropyl, 2-oxobutyl,2-acetylethyl, 1-carbonylisopropyl, and cyclopentanecarbonyl. Examplesof the alkyl group the methylene chain of which is interrupted by —OCO—include acetoxy, propionyloxy, and butyryloxy. Examples of the alkylgroup the methylene chain of which is interrupted by —COO— includemethoxycarbonyl, ethoxycarbonyl, and isopropyloxycarbonyl.

Examples of the optionally substituted aryl group having 6 to 20 carbonatoms represented by R¹, R², R³, and R⁴ in general formulae (II) and(III) include phenyl, naphthyl, and biphenyl. Examples of the aryl groupof which the bond to the benzene ring is interrupted by —O— includephenoxy, 1-naphthoxy, and 2-naphthoxy. Examples of the aryl group ofwhich the bond to the benzene ring is interrupted by —S— includephenylthio, 1-naphthylthio, and 2-naphthylthio. Examples of the arylgroup of which the bond to the benzene ring is interrupted by —SO₂—include phenylsulfone, 1-naphthylsulfone, and 2-naphthylsulfone.Examples of the aryl group of which the bond to the benzene ring isinterrupted by —CO— include benzoyl, 1-naphthoyl, and 2-naphthoyl.Examples of the aryl group of which the bond to the benzene ring isinterrupted by —OCO— include benzoyloxy, 1-naphthoyloxy, and2-naphthoyloxy. Examples of the aryl group of which the bond to thebenzene ring is interrupted by —COO— include phenoxycarbonyl and1-naphthoxycarbonyl.

Examples of the optionally substituted heterocyclic ring having 4 to 20carbon atoms represented by R¹, R², R³, and R⁴ in general formulae (II)and (III) include pyrrolyl, pyridyl, pyrimidyl, pyridazyl, piperazyl,piperidyl, pyranyl, pyrazolyl, triazyl, pyrrolidyl, quinolyl,isoquinolyl, imidazolyl, benzimidazolyl, triazolyl, furyl, furanyl,benzofuranyl, thienyl, thiophenyl, benzothiophenyl, thiadiazolyl,thiazolyl, benzothiazolyl, oxazolyl, benzoxazolyl, isothiazolyl,isoxazolyl, indolyl, julolidyl, morpholinyl, thiomorpholinyl,2-pyrrolidinon-1-yl, 2-piperidon-1-yl, 2,4-dioxyimidazolidin-3-yl, and2,4-dioxyoxazolidin-3-yl.

Examples of the optionally substituted arylalkyl group having 7 to 20carbon atoms represented by R¹, R², R³, and R⁴ in general formulae (II)and (III) include benzyl, phenethyl, 2-phenylpropyl, diphenylmethyl,triphenylmethyl, and 4-chlorophenylmethyl. Examples of the arylalkylgroup the methylene chain of which is interrupted by —O— includebenzyloxy, phenoxymethyl, phenoxyethyl, 1-naphthylmethoxy,2-naphthylmethoxy, and 1-anthrylmethoxy. Examples of the arylalkyl groupthe methylene chain of which is interrupted by —S— include benzylthio,phenylthiomethyl, and phenylthioethyl. Examples of the arylalkyl groupthe methylene chain of which is interrupted by —SO₂— is exemplified bybenzylsulfonyl. Examples of the arylalkyl group the methylene chain ofwhich is interrupted by —CO— include benzylcarbonyl, phenethylcarbonyl,and 1-naphthylmethylcarbonyl. Examples of the arylalkyl group themethylene chain of which is interrupted by —OCO— include a phenylacetategroup and a 1-naphthylacetate group. Examples of the arylalkyl group themethylene chain of which is interrupted by —COO— includebenzyloxycarbonyl and phenethyloxycarbonyl.

Adjacent two of R¹, R², R³, and R⁴ in general formulae (II) and (III)may be taken together to form a cyclic structure. Examples of such acyclic structure include benzene ring, cyclopentane ring, cyclohexanering, cycloheptane ring, cyclooctane ring, imidazole ring, thiazolering, pyrazole ring, oxazole ring, isoxazole ring, thiophene ring, furanring, pyrrole ring, pyridine ring, piperazine ring, piperidine ring,morpholine ring, pyrazine ring, pyrone ring, and pyrrolidine ring. Thesecyclic structure may be substituted.

Examples of the alkyl group having 1 to 20 carbon atoms and the arylgroup having 6 to 20 carbon atoms represented by R and R′ and the cyclicstructure formed by R or R′ and the adjacent R¹, R², R³, or R⁴ ingeneral formulae (II) and (III) are the same as listed with respect togeneral formula (I).

Examples of the substituents of the alkyl group having 1 to 20 carbonatoms, the aryl group having 6 to 20 carbon atoms, the heterocyclic ringhaving 4 to 20 carbon atoms, and the arylalkyl group having 7 to 20carbon atoms in general formulae (II) and (III) are the same as thoselisted as substituents with respect to general formula (I). When thesubstituent of the alkyl, aryl, or arylalkyl as R¹, R², R³, or R⁴contains a carbon atom, the total number of carbon atoms inclusive ofthat of the substituent shall fall within the respective ranges recited.

Specific examples of the Schiff base type compounds of general formulae(I) to (III) include, but are not limited to, the following compoundsnumbered 1 through 56.

The Schiff base type compound of general formula (I) is not limited bythe process of preparation and can be obtained by any processes makinguse of well-known reactions. For example, the compound may besynthesized by the reaction between a corresponding aldehyde compoundand a corresponding amine compound as illustrated in the reaction schemeof [Chem. 9] below.

wherein ring A represents an aromatic ring, an aliphatic ring, or aheterocyclic ring; Ar represents a 5- or 6-membered heterocyclic oraromatic ring: the aliphatic ring represented by ring A and the aromaticring and the heterocyclic ring represented by ring A or Ar beingoptionally fused to a ring or optionally substituted.

The Schiff base type compound of the invention is suitable for use as acolorant absorbing light of from 300 nm to 700 nm. It is useful, forexample, as a colorant in an optical recording layer of DVD-Rs; acolorant for optical filters used in image displays, such as liquidcrystal displays (LCDs), plasma display panels (PDPs), electroluminescence displays (ELDs), cathode ray tube displays (CRTs),fluorescent display tubes, and field emission displays; a light-emittingcolorant for organic electro luminescence; a color toner, an inkjet ink,a colorant for coatings, an LED lamp, and an electro luminescence lamp.The Schiff base type compound of the invention may also be used as aspectral sensitizer for photoelectric devices or silver saltphotographic materials or a sensitizer for optical reactions.

The Schiff base type compound of the invention may be incorporated intothe light emitting portion of the image display devices. For instance,in application to an EL device including an anode, a cathode, and aplurality of layers between the anode and the cathode, the Schiff basetype compound is incorporated into at least one of the layers. TheSchiff base type compound may be incorporated into the photoelectricdevice. For instance, the compound may be adsorbed onto the surface of asemiconductor, e.g., titanium oxide or zinc oxide, to generateelectricity.

The Schiff base type compound of the invention converts light of 300 to700 nm to fluorescence of 400 to 750 nm and is therefore useful as afluorescent material. The Schiff base type compound of the inventionemits fluorescence even in its solid state and converts light of 350 to650 nm to fluorescence of 400 to 750 nm and is therefore useful as afluorescent pigment.

The coloring material of the invention contains at least one Schiff basetype compound of the invention and, where needed, may further containother colorants than the Schiff base type compound of the invention. Thecoloring material is a composition especially necessary for thepreparation of a color conversion layer or a light absorbing layer. Theform of the coloring material is not particularly limited and may be acoating liquid, a filler, a sealant, an adhesive, or the like form.

The Schiff base type compound content in the coloring material designedfor making a color conversion layer is preferably 0.001% to 50% by mass,more preferably 0.01% to 20% by mass, based on the solids content (i.e.,non-solvent content). The Schiff base type compound content in thecoloring material designed for making a light absorbing layer ispreferably 0.001% to 50% by mass, more preferably 0.01% to 20% by mass,based on the solids content.

If desired, the coloring material of the invention may contain a binder(e.g., a photocuring resin, a thermosetting resin, or a thermoplasticresin), a photo stabilizer, a curing agent, an IR absorber, a UVabsorber, an antioxidant, a surfactant, an antistatic agent, a flameretarder, a lubricant, a heavy metal deactivator, hydrotalcite, anorganic carboxylic acid, a coloring agent, a processing aid, inorganicadditives, a filler, a clarifier, a nucleating agent, a crystallizingagent, a quencher, a solvent, and so forth. Of the Schiff base typecompounds of the invention those which emit fluorescence will be madeusable in the coloring material designed for making a color conversionlayer by adding a quencher to the coloring material.

The other colorants that may be used in combination are not particularlylimited and include, for example, cyanine colorants, pyridine colorants,oxazine colorants, coumarin colorants, coumarin dyes, naphthalimidecolorants, pyromethene colorants, perylene colorants, pyrene colorants,anthracene colorants, styryl colorants, rhodamine colorants, azocolorants, quinone colorants, squarylium colorants, diketopyrrolopyrrolecolorants, iridium complex colorants, and europium complex colorants.The content of the other colorants in the coloring material of theinvention is preferably 0.1 to 50 parts by mass per 100 parts by mass ofthe Schiff base type compound of the invention.

Examples of the quencher include, but are not limited to, aminiumcolorants, iminium colorants, cyanine colorants, and transition metalchelate compounds. The content of the quencher in the coloring materialof the invention is preferably 1 to 5000 parts by mass, more preferably10 to 1000 parts by mass, per 100 parts by mass of the Schiff base typecompound.

Examples of the solvent include, but are not limited to, water,alcohols, diols, ketones, esters, ethers, aliphatic or alicyclichydrocarbons, aromatic hydrocarbons, cyano-containing hydrocarbons, andhalogenated aromatic hydrocarbons.

The color conversion layer according to the invention contains thecoloring material of the invention and has the characteristic ofabsorbing light and emitting light as fluorescence having a longerwavelength than that of the light absorbed. The form of the colorconversion layer is not particularly limited and may be, for example,film or pellets.

More specifically, the color conversion layer of the invention may be asingle layer of the Schiff base type compound alone or in admixture withother colorant(s) formed on a substrate or a laminate composed of such alayer and other layer(s) formed on a substrate.

The single layer or the laminate is prepared by forming a coating layeron a permanent or temporary substrate by, for example, evaporationdeposition, sputtering, solution processes using a solution or adispersion, such as dip coating, air knife coating, curtain coating,roller coating, wire bar coating, gravure coating, and spin coating, orextrusion.

The color conversion layer of the invention may be a film or a filterprepared from a mixture of the Schiff base type compound dissolved ordispersed in a binder resin.

The film or filter is prepared by applying a mixture of the Schiff basetype compound dissolved or dispersed in a binder resin to a permanent ortemporary substrate by the same method as described for the preparationof a single layer or a laminate. The film can be a self-supporting film,which is obtained by forming the film on a temporary substrate by theabove described method and peeling the film from the temporarysubstrate.

Examples of the binder resin include natural polymeric materials, suchas gelatin, casein, starch, cellulose derivatives, and alginic acid;synthetic polymers, such as polymethyl methacrylate, polyvinyl butyral,polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl chloride,styrene-butadiene copolymers, polystyrene, polycarbonate, polyamide,ethylene-vinyl acetate copolymer resins, polyfluorene reins, andsilicone resins; and adhesives of rubber, acrylic or silicone type.

The solvent is not particularly limited, and examples of suitablesolvents include those described with reference to the coloring materialof the invention.

A self-supporting film can also be directly molded from a mixture of theSchiff base type compound of the invention and a polymer by extrusion,casting, or calendering. Examples of useful polymers include celluloseesters, such as diacetyl cellulose, triacetyl cellulose (TAC), propionylcellulose, butyryl cellulose, acetylpropionyl cellulose, andnitrocellulose; polyamides; polycarbonates; polyesters, such aspolyethylene terephthalate, polyethylene naphthalate, polybutyleneterephthalate, poly-1,4-cyclohexanedimethylene terephthalate,polyethylene-1,2-diphenoxyethane 4,4′-dicargoxylate, and polybutyleneterephthalate; polystyrene; polyolefins, such as polyethylene,polypropylene, and polymethylpentene; acrylic resins, such as polymethylmethacrylate; polysulfone; polyether sulfone; polyether ketone;polyether imide; polyoxyethylene; and norbornene resins.

The color conversion layer may also be prepared by mixing the Schiffbase type compound of the invention with a photocuring resin and/orthermosetting resin and a photopolymerization initiator and/or a thermalcuring agent and applying light and/or heat to form a cured film.

In the case where the color conversion layer of the invention is forapplications involving patterning by wet etching, it is preferred forthe color conversion layer to contain the Schiff base type compound offormulae (I), (II) or (III) and a photocuring or photo- andthermal-curing resin (i.e., resist). A cured product of the photocuringor photo- and thermal-curing resin (resist) functions as a binder of thecolor conversion film after patterning. To facilitate smooth patterning,the photocuring or photo- and thermal-curing resin is desirably solublein an organic solvent or an alkali solution in an unexposed state.Examples of useful photocuring or photo- and thermal-curing resin(resist) include (1) a composition containing a polyfunctional acrylicmonomer and oligomer having at least two acryloyl or methacryloyl groupsand a photo- or thermal polymerization initiator, (2) a compositioncontaining a polyvinyl succinate and a sensitizer, (3) a compositioncontaining an acyclic or cyclic olefin and a bisazide (nitrene isgenerated to crosslink the olefin), and (4) a composition containing anepoxy-containing monomer and an acid generator. The composition (1) thatcontains a polyfunctional acrylic monomer and oligomer and a photo- orthermal polymerization initiator is particularly preferred; for it iscapable of high definition patterning and, after polymerization andcure, provides high reliability in terms of, e.g., solvent resistanceand heat resistance.

The light absorbing layer according to the invention is made of thecoloring material of the invention and has the characteristic ofabsorbing light in the visible region. The light absorbing layer of theinvention may be in any form such as those described with reference tothe color conversion layer.

The color conversion filter according to the invention includes one ormore color conversion layers at least one of which contains the Schiffbase type compound of the invention. The color conversion filter of theinvention is applicable to devices having a light emitting portion. Whenapplied to, for example, an organic electro luminescence displays, thecolor conversion filter converts light from a device emittingmonochromatic light in the region between near ultraviolet and blue toblue, green, or red light only in necessary regions of the devicethereby to achieve full color display. When applied to organic EL lampsor LED lamps, the color conversion filter converts the whole or part ofnear ultraviolet to blue light to light of longer wavelengths to obtainwhite light. In applications to liquid crystal displays, the colorconversion filter may be incorporated into a polarizer, a light guidepanel, or a diffuser, disposed between optical films, or disposed as alaminate with another color conversion layer, so that the light incidentto be absorbed by a color conversion filter is previously converted toeffective light, thereby to improve brightness and save the power.

Capable of making a desired color, the color conversion filter of theinvention is also useful in LED lamps, colorant lasers, and the like.The color conversion filter is also applicable to devices having aphotoelectric element. When applied to, for example, a solar cell, it iscapable of absorbing light of wavelengths with which the photoelectricelement achieves only low photovoltaic efficiency and converting it tolight of wavelengths with which the photoelectric element achieves highphotovoltaic efficiency.

The light absorbing filter according to the invention includes one ormore light absorbing layers at least one of which contains the Schiffbase type compound of the invention. The light absorbing filter of theinvention is used as an optical element of an optical filter for imagedisplay devices, such as liquid crystal displays (LCDs), plasma displaypanels (PDPs), electro luminescence displays (ELDs), cathode ray tubedisplays (CRTs), fluorescent display tubes, and field emission displays.

Configurations of preferred embodiments of the light absorbing filter ofthe invention are illustrated in FIGS. 1( a), 1(b), and 1(c). The lightabsorbing filter may include a substrate 100 and an optically functionallayer 120 containing the Schiff base type compound of the invention andmay optionally include, when needed, a primer layer 110, anantireflective layer 130, a hardcoat layer 140 and/or a lubricatinglayer 150. As illustrated in FIG. 1( a), a primer layer 110, anoptically functional layer 120, an antireflective layer 130, a hardcoatlayer 140, and a lubricating layer 150 may be stacked in that order onone side of a substrate 100. As illustrated in FIG. 1( b), a primerlayer 110, an optically functional layer 120, a hardcoat layer 140 and alubricating layer 150 may be stacked in that order on one side of asubstrate 100, and a primer layer 110, an antireflective layer 130, anda lubricating layer 150 may be stacked in that order on the other sideof the substrate 100. As illustrated in FIG. 1( c), a primer layer 110,an antireflective layer 130, a hardcoat layer 140, and a lubricatinglayer 150 may be stacked in that order on one side of an opticallyfunctional substrate 105 containing the Schiff base type compound of theinvention.

The substrate 100 may be of an inorganic material such as glass or apolymer such as illustrated above with reference to the color conversionlayer. The substrate 100 preferably has a visible light transmittance ofat least 80%, more preferably 86% or more; a haze of 2% or less, morepreferably 1% or less; and a refractive index of 1.45 to 1.70. Thethickness of the substrate 100 is decided as appropriate to the intendeduse and the like and is generally preferably, but not limited to, from10 to 10000 μm.

The optically functional substrate 105 used in the configuration of FIG.1( c) may be the above-described self-supporting light absorbing layerof the invention. The optically functional substrate 105 preferably hasa haze of 2% or less, more preferably 1% or less, and a refractive indexof 1.45 to 1.70. The thickness of the optically functional substrate 105is decided as appropriate to the intended use and the like and isgenerally preferably, but not limited to, from 10 to 10000 μm.

The substrate 100 and the optically functional substrate 105 may containan IR absorber, a UV absorber, inorganic particles, and the like. Thesubstrate 100 and the optically functional substrate 105 may besubjected to a surface treatment, such as chemical treatment, mechanicaltreatment, corona discharge treatment, flame treatment, UV irradiation,high frequency treatment, glow discharge treatment, active plasmatreatment, laser treatment, mixed acid treatment, and ozone oxidation.

The primer layer 110 is provided to enhance the adhesion between thesubstrate 100 or the optically functional substrate 105 (thesesubstrates will sometimes be referred inclusively to “substrate”) and anadjoining layer, e.g., the optically functional layer 120 and/or theantireflective layer 130. The primer layer 110 may be a layer of apolymer having a glass transition temperature of −60° to 60° C., a layerwith a rough surface on its side opposite to the substrate, or a layercontaining a polymer having affinity for both the substrate and theadjoining layer. The primer layer 110 may be provided to improve theaffinity between an adhesive for attaching the light absorbing filter toa display (light source) and the light absorbing filter. The thicknessof the primer layer is preferably 2 nm to 20 μm, more preferably 5 nm to5 μm, even more preferably 20 nm to 2 μm, still more preferably 50 nm to1 μm, and most preferably 80 nm to 300 nm.

The primer layer 110 containing a polymer with a glass transitiontemperature of −60° to 60° C. bonds the substrate and the adjoininglayer by its own tackiness. The polymer having a glass transitiontemperature of −60° to 60° C. is obtained by homo- or copolymerizationof vinyl chloride, vinylidene chloride, vinyl acetate, butadiene,neoprene, styrene, chloroprene, an acrylic ester, a methacrylic ester,acrylonitrile, or methyl vinyl ether. The glass transition temperatureof the polymer is preferably −60° to 50° C., more preferably −60° to 40°C., even more preferably −60° to 30° C., still more preferably −60° to25° C., and most preferably −60° to 20° C. The primer layer preferablyhas an elastic modulus at 25° C. of 1 to 1000 MPa, more preferably 5 to800 MPa, even more preferably 10 to 500 MPa.

The primer layer 110 that has a rough surface on its side opposite tothe substrate bonds the substrate and the adjoining layer by themechanical action of its surface roughness. The primer layer 110 with arough surface is formed easily by application of a polymer latex. Thelatex preferably has an average particle size of 0.02 to 3 μm, morepreferably 0.05 to 1 μm.

The primer layer 110 may also be a layer of a polymer having affinityfor the binder polymer of the adjoining layer. It is preferred for thepolymer to have affinity for the substrate as well. Examples of apolymer with affinity for the binder polymer of, e.g., the opticallyfunctional layer 120 include acrylic resins, cellulose derivatives,gelatin, casein, starch, polyvinyl alcohol, soluble nylon, and polymerlatices. Two or more primer layers 110 may be provided. The primer layer110 may contain a solvent that swells the substrate 100, a mattingagent, a surfactant, an antistatic agent, a coating aid, a hardeningagent, and so forth.

The optically functional layer 120 may be formed of the light absorbinglayer of the invention. The optically functional layer 120 is providedon the substrate 100 or the primer layer 110 formed on the substrate100. The optically functional layer 120 may be formed by bonding aself-supporting film to the primer layer 110 or the substrate 100. Thethickness of the optically function layer 120 is decided as appropriateto the intended use and the like and is generally preferably, but notlimited to, from 0.1 to 100 μm.

Containing the Schiff base type compound of the invention, the opticallyfunctional layer 120 or the optically functional substrate 105 can bedesigned to function as a light absorbing layer that absorbs light inthe wavelength range of from 400 nm to 700 nm. In this case, theoptically functional layer 120 preferably contains a quencher in orderto quench the fluorescence generated by the Schiff base type compound onabsorbing light of the wavelength range recited. The quencherspreviously described with reference to the coloring material may beused. This light absorbing layer may be designed to have a desired hueby adding, to the optically functional layer 120, a colorant absorbinglight of other wavelengths, which is selected from the compoundsdescribed above as other colorants with respect to the coloringmaterial.

In the cases where the optically functional layer 120 is designed tofunction as a light absorbing layer, the amount of the Schiff base typecompound of the invention to be used is suitably 1 to 1000 mg,preferably 5 to 300 mg, per square meter of the light absorbing filter.With the recited amount of the Schiff base type compound, the opticallyfunctional layer 120 exhibits a sufficient light absorbing effect aswell as a suitable optical density to provide good display quality andbrightness. In the case where the optically functional substrate 105 asin the configuration of FIG. 1( c) is used as a light absorbing layer,too, the Schiff base type compound of the invention is preferably usedin an amount falling within the recited range.

The antireflective layer 130 is provided to prevent reflection on thelight absorbing filter of the invention to improve the transmittance.The antireflective layer 130 may be a low refractive index layer formedof a material having a lower refractive index than the substrate 100.The refractive index of such a low refractive index layer is preferably1.20 to 1.55, more preferably 1.30 to 1.50. The thickness of the lowrefractive index layer is preferably 50 to 400 nm, more preferably 50 to200 nm. The low refractive index layer may be a layer made of afluoropolymer with a low refractive index, a layer formed by a sol-gelprocess, or a layer containing particles. The layer containing particleshas microvoids between the particles or in the particles. The porosityof the layer containing particles is preferably 3% to 50% by volume,more preferably 5% to 35% by volume.

The antireflective layer 130 can be formed of a laminate of one or morelow refractive index sublayers and one or more medium or high refractiveindex sublayers to prevent reflection of light of broader wavelengthrange. The refractive index of a high refractive index sublayer ispreferably 1.65 to 2.40, more preferably 1.70 to 2.20. The refractiveindex of a medium refractive sublayer is set to be the intermediatebetween the refractive indices of the low and the high refractivesublayers and preferably ranges from 1.50 to 1.90, more preferably 1.55to 1.70. The thickness of the medium or high refractive index sublayeris preferably 5 nm to 100 μm, more preferably 10 nm to 10 μm, even morepreferably 30 nm to 1 μm. The medium or high refractive index sublayerpreferably has a haze of 5% or less, more preferably 3% or less, evenmore preferably 1% or less, unless it is functionalized for antiglare.

The medium and the high refractive index sublayers are formed by usingpolymer binders having relatively high refractive indices, such aspolystyrene, styrene copolymers, polycarbonates, melamine resins, phenolresins, epoxy resins, and polyurethanes obtained by the reaction betweena cyclic (alicyclic or aromatic) isocyanate and a polyol. Polymershaving a cyclic (aromatic, heterocyclic or alicyclic) group and polymershaving a halogen atom except fluorine as a substituent also have highrefractive indices. Polymers may be formed from monomers having a doublebond introduced therein and thereby capable of radical polymerization.

Fine inorganic particles may be dispersed in the above recited polymerbinders to increase the refractive index. Inorganic particles having arefractive index of 1.80 to 2.80 are used preferably. Such inorganicparticles are preferably prepared from metal oxides or sulfides, such astitanium oxide (including rutile, rutile/anatase mixed crystals,anatase, and amorphous oxide), tin oxide, indium oxide, zinc oxide,zirconium oxide, and zinc sulfide. Preferred of them are titanium oxide,tin oxide, and indium oxide. The inorganic particles may contain themetal oxide or sulfide as a major component and other elements. The term“major component” means a component present in the particles at thehighest weight percentage. Other elements that may be present includeTi, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P, andS. The medium or high refractive index sublayer can also be formed byusing inorganic materials that are dispersible in a solvent or liquidper se and are capable of forming a film, such as alkoxides of variouselements, salts of organic acids, coordination compounds having acoordinating compound bonded (e.g., chelate compounds), and inorganicactive polymers.

The surface of the antireflective layer 130 may be endowed with anantiglare function for scattering incident light thereby preventing thesurrounding environment from reflecting on the antireflective layer. Anantiglare function can be imparted to the antireflective layer 130 by,for example, finely texturing the surface on which the antireflectivelayer 130 is to be formed (e.g., the surface of the primer layer 110) orembossing or otherwise roughening the surface of the antireflectivelayer 130. The antireflective layer functionalized for antiglare usuallyhas a haze of 3% to 30%.

The hardcoat layer 140 is provided to protect the underlying layer(s)(i.e., the optically functional layer 120 and/or the antireflectivelayer 130) and formed of a material having higher hardness than thesubstrate 100. The hardcoat layer 140 preferably contains a crosslinkedpolymer. The hardcoat layer 140 can be formed using acrylic, urethane orepoxy polymers, oligomers or monomers, such as UV curing resins. Thehardcoat layer 140 can also be made of a silica-based material. Thethickness of the hardcoat layer 140 is preferably 0.1 to 100 μm, morepreferably 1 to 30 μm.

The lubricating layer 150 may be provided on the surface of the lightabsorbing filter of the invention. The lubricating layer 150 impartsslip properties to the surface of the light absorbing filter therebyimproving scratch resistance. The lubricating layer 150 can be formedusing an organopolysiloxane (e.g., silicone oil), a natural wax, apetroleum wax, a higher fatty acid metal salt, or a fluorine-containinglubricant, or a derivative thereof. The lubricating layer 150 preferablyhas a thickness of 2 to 20 nm.

The primer layer 110, the antireflective layer 130, the hardcoat layer140, and the lubricating layer 150 may be formed by any wet processesknown in the art, such as dip coating, air knife coating, curtaincoating, roller coating, wire bar coating, gravure coating, andextrusion coating. When the hardcoat layer 140 is formed from asilica-based material, it may be formed by any film formation techniquesknown in the art, such as evaporation deposition, sputtering, CVD, andlaser ablation.

The layers composing the light absorbing filter of the invention may beformed sequentially, or two or more of them may be formedsimultaneously.

The color-converting light-emitting device according to the invention isnot particularly limited as long as it includes a light emitting portion(light source) and, as a color conversion portion, the color conversionlayer or color conversion filter of the invention. Otherwise, it isidentical to conventional color converting light emitting devices. Apreferred embodiment of the color converting light emitting device for,for instance, color display is illustrated in FIG. 2. The colorconverting light emitting device of FIG. 2 includes a substrate 50 and alight emitting layer 40 on the substrate 50. The means for causing thelight emitting layer 40 to emit light is not particularly limited. Forexample, a light emitting layer of an electro luminescent (EL) device iscaused to emit light by applying an electric current between electrodeshaving the light emitting layer therebetween.

A red color-conversion layer 20R, a green color-conversion layer 20G,and a blue color-conversion layer 20B are provided on the light emittinglayer 40 to convert the color of the light emitted from the lightemitting layer 40. At least one of these color conversion layers is thecolor conversion layer or color conversion filter of the presentinvention. The color conversion layer or the color conversion filter maybe the red, green, or blue color-conversion layer 20R, 20G, or 20Baccording to the desired wavelength after conversion. The colorconversion layer or filter may be a color conversion layer or filterusing a film formed from a resin composition in which the Schiff basetype compound of the invention is dissolved or dispersed in a binderresin.

If appropriate, a red, a green, and a blue color filter layer 10R, 10G,and 10B may be provided. These color filter layers are provided where itis required to optimize the chromatic coordinate or purity of the lightconverted through the red, green, or blue color conversion layer.

A black mask 30 is provided between the stacks of the red, green or bluecolor conversion layer 20R, 20G, or 20B and the red, green, or bluecolor filter layer 10R, 10G, or 10B. The black mask 30 is effective inincreasing contrast.

The substrate 50 may be of an inorganic material such as glass or thepolymer described. To facilitate forming electrodes that cause the lightemitting layer 40 to emit light, a glass substrate is preferred.

The color filter layers 10R, 10B, and 10G have a function to transmitonly light rays of desired wavelengths. The color filter layers 10R,10B, and 10G are effective in blocking light rays from the light sourcethat remain unconverted and improving the chromatic purity of the lightrays having passed through the color conversion layers 20R, 20G, and20B. The color filter layers may be formed of the materials of colorfilters for liquid crystal displays.

A color converting light emitting device for color display is composedof a plurality of sets of pixels arrayed in a matrix arrangement on asubstrate 10, each set comprising the R, G, and B color-converting lightemitting elements illustrated in FIG. 2. The pattern of arrangement ofthe color conversion filter layers depends on the intended use of thedevice. A red, a green, and a blue pixel having a rectangular, acircular, or any shape intermediate therebetween make one set, and thesets may be arranged in a matrix on the entire surface of the substrate50. Or, color conversion layers of two different colors may be arrangedin finely partitioned sections in an appropriate area ratio to display amonochromatic color that is not achieved with a color conversion layerof single color.

While FIG. 2 shows an embodiment in which a red, a green, and a bluecolor conversion layer are used, when a light emitting element thatemits blue to green light is used as a light source, a color filterlayer may be used alone without a color converting layer for blue. Whenthe light from such a light source contains a sufficient amount of greenregion rays, light from the light source may be output only through agreen color filter without using a color conversion layer for green.

Any light source that emits light in the near ultraviolet to visibleregion, preferably the near ultraviolet to bluish green region may beused as the light emitting portion. Examples of such a light sourceinclude an organic electro luminescent displays, a plasma light emittingdevice, a cold-cathode fluorescent lamp, a discharge lamp (e.g., a highpressure or ultrahigh pressure mercury lamp or a xenon lamp), and anlight emitting device.

When the color converting light emitting device of the invention has acolor filter layer as illustrated in FIG. 2, the light emitting portionis disposed on the side of the color conversion layer.

When the color converting light emitting device of the invention has nocolor filter layer and uses, for example, the light absorbing filtershown in FIG. 1 (which contains no color filter layer) as a colorconversion portion, the light emission portion may be disposed on eitherside of the light absorbing filter. When a color conversion layer itselfis used as a color conversion portion, the conversion layer may bestacked directly on the surface of the light source.

The photoelectric device according to the invention is not particularlylimited as long as it includes a photoelectric element and the colorconversion filter of the invention. Otherwise, it is identical toconventional color photoelectric devices. A solar cell as a preferredembodiment of the photoelectric device of the invention is illustratedin FIG. 3. In order for a photoelectric element 240 to generateelectricity at high efficiency, the neighboring layers including atopsheet layer 200, a transparent substrate 210, a filler layer 220, alight collecting film 230, and a backsheet layer 250 can be made into acolor conversion filter. That is, the effects of the invention areobtained by incorporating the Schiff base type compound of the inventioninto the element(s) near the photoelectric element. A color conversionlayer may separately be provided to obtain the same effects. Forexample, a color conversion layer may be provided between layers usingan adhesive containing the Schiff base type compound of the invention.

The photoelectric device of the invention is exemplified by, but notlimited to, a solar cell, including a silicon solar cell, a compoundsolar cell, and an organic solar cell.

EXAMPLES

The present invention will now be illustrated in greater detail withreference to Preparation Examples, Examples, and Evaluation Examples,but it should be understood that the invention is not construed as beinglimited thereto.

Preparation Examples 1-1 to 1-12 Preparation of Compound Nos. 1 Through9, 11, 55, and 56

In a reaction flask, 0.01 mol of each of the starting compounds shown inTable 1 or 2 and numbered 1 through 9, 11, 55, and 56 and 0.012 mol ofdiisopropylethylamine were dissolved in 12 g of dichloromethane. To thesolution was added dropwise 0.012 mol of BF₃/Et₂O under cooling in awater bath over a period of 10 minutes, and the mixture was stirred forthe reaction time shown in Table 1 or 2. Twenty milliliters of water wasadded, and the stirring was continued for an additional 1 hour period.After oil-water separation, the oily phase was dried over Na₂SO₄,filtered, and concentrated. The residue was purified by columnchromatography using chloroform as a developing solvent, and the columneluate was concentrated and dried in vacuo at 60° C. for 1 hour to givea Schiff base type compound (compound No. 1 through 9, 11, 55, or 56,respectively) of the invention having the appearance shown in Table 1 or2 in the yield shown in Table 1 or 2. The resulting compounds wereidentified by ¹H-NMR and mass spectrometry (MALDI-TOF-MS). The resultsof the identification are shown in Tables 3 and 4.

TABLE 1 Desired Reaction Compound Starting Compound Time AppearanceYield Prepn. Example 1-1 Compound No. 1

1.5 h pale yellow solid 83% Prepn. Example 1-2 Compound No. 2

4.5 h pale yellow solid 42% Prepn. Example 1-3 Compound No. 3

  2 h orange solid 54% Prepn. Example 1-4 Compound No. 4

2.5 h white solid 33% Prepn. Example 1-5 Compound No. 5

  2 h pale yellow solid 73% Prepn. Example 1-6 Compound No. 6

5.5 h yellow solid 73%

TABLE 2 Desired Reaction Compound Starting Compound Time AppearanceYield Prepn. Example 1-7 Compound No. 7

15 h orange solid 45% Prepn. Example 1-8 Compound No. 8

 3 h orange solid 65% Prepn. Example 1-9 Compound No. 9

 5 h yellow solid 82% Prepn. Example 1-10 Compound No. 11

 2 h pale yellow solid 66% Prepn. Example 1-11 Compound No. 55

24 h yellow solid 61% Prepn. Example 1-12 Compound No. 56

 7 h yellow solid 73%

TABLE 3 ¹H-NMR(CDCl₃) Chemical Shift; ppm (multiplicity, number ofprotons) Compound No. 1 7.04 (t, 1H), 7.17 (d, 1H), 7.44-7.56 (m, 6H),7.67 (t, 1H), 8.44 (s, 1H) Compound No. 2 1.24 (t, 6H), 3.45 (q, 4H),6.24 (d, 1H), 6.35 (dd, 1H), 7.22 (d, 1H), 7.33 (t, 1H), 7.42 (t, 2H),7.49 (d, 2H), 8.03 (s, 1H) Compound No. 3 1.14-1.24 (m, 12H), 3.33-3.46(m, 8H), 6.24 (d, 1H), 6.32 (dd, 1H), 6.65 (d, 2H), 7.18 (d, 1H), 7.34(d, 2H), 7.98 (s, 1H) Compound No. 4 7.07 (t, 1H), 7.18 (d, 1H), 7.53(dd, 1H), 7.68-7.80 (m, 5H), 8.47 (s, 1H) Compound No. 5 1.25 (t, 6H),3.46 (q, 4H), 6.21 (d, 1H), 6.38 (dd, 1H), 6.77 (tt, 1H), 7.08 (d, 2H),7.23 (d, 1H), 8.01 (s, 1H) Compound No. 6 1.25 (t, 6H), 3.46 (q, 4H),6.22 (d, 1H), 6.37 (dd, 1H), 7.23 (d, 1H), 7.61 (d, 2H), 7.67 (d, 2H),8.04 (s, 1H) Compound No. 7 1.27 (t, 6H), 2.48 (s, 3H), 3.49 (q, 4H),6.21 (d, 1H), 6.43 (dd, 1H), 7.26 (d, 1H), 7.33 (d, 1H), 7.61 (s, 1H),7.75 (d, 1H), 9.12 (s, 1H) Compound No. 8 1.27 (t, 6H), 3.49 (q, 4H),6.20 (d, 1H), 6.44 (dd, 1H), 7.31-7.36 (m, 2H), 7.46 (t, 1H), 7.82 (d,1H), 7.87 (d, 1H), 9.15 (s, 1H) Compound No. 9 1.19 (t, 6H), 3.39 (q,4H), 6.68 (d, 2H), 7.00 (t, 1H), 7.13 (d, 1H), 7.40-7.46 (m, 3H), 7.58(t, 1H), 8.34 (s, 1H) Compound No. 11 1.35 (s, 9H), 1.57 (s, 9H), 7.82(d, 1H), 8.04-8.18 (m, 6H), 8.20-8.28 (m, 3H), 8.48 (s, 1H) Compound No.55 8.11 (d, 1H), 8.08 (d, 1H), 7.99 (s, 1H), 7.61 (d, 1H), 7.47 (t, 1H),7.40-7.37 (m, 2H), 7.25-7.20 (m, 1H), 6.80 (s, 1H), 4.35 (q, 2H),3.33-3.29 (m, 4H), 2.83 (t, 2H), 2.67 (t, 3H), 1.94-1.91 (m, 4H), 1.42(t, 3H) Compound No. 56 8.01 (s, 1H), 7.35 (d, 2H), 7.28-7.23 (m, 4H),7.18 (d, 1H), 7.11-7.01 (m, 8H), 6.32 (d, 1H), 6.21 (s, 1H), 3.35 (t,4H), 1.66-1.55 (m, 4H), 1.41-1.31 (m, 4H), 0.97 (t, 6H)

TABLE 4 Mass Spectrometry (MALDI-TOF-MS) Calculated Found Value CompoundNo. 1 245.04 246.2 [M+] Compound No. 2 316.16 317.3 [M+] Compound No. 3387.28 387.4 [M+] Compound No. 4 313.04 314.2 [M+] Compound No. 5 352.14353.3 [M+] Compound No. 6 384.16 384.0 [M−] Compound No. 7 387.26 388.3[M+] Compound No. 8 373.24 374.3 [M+] Compound No. 9 316.16 317.3 [M+]Compound No. 11 481.40 481.5 [M+] Compound No. 55 457.34 457.3 [M+]Compound No. 56 539.48 539.5 [M+]

Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3

Fluorescence spectra of Schiff base type compound Nos. 1 to 9, 11, 55,and 56 obtained in Preparation Examples 1-1 to 1-12 and comparativecompounds 1 to 3 shown [Chem. 10] below were determined in a toluenesolvent using a spectrophotometer U-3010 (for absorption spectrometry)and a fluorescence spectrophotometer F4500 (for fluorescencespectrometry), both from Hitachi High-Technologies Corp. The results offluorescence spectrophotometry are shown in Table 5.

TABLE 5 Fluorescence Schiff Base λ_(max) ε Maximum Fluorescence DensityCompound (nm) (M⁻¹cm⁻¹) (nm) Intensity (M) Example Compound 365 8.60 ×10³ 465.4 24.2 3.72 × 10⁻⁵ 1-1 No. 1 Example Compound 395 5.17 × 10⁴446.4 43.8 7.21 × 10⁻⁶ 1-2 No. 2 Example Compound 421 3.88 × 10⁴ 557.821.2 1.14 × 10⁻⁵ 1-3 No. 3 Example Compound 375 8.11 × 10³ 478.2 76.66.08 × 10⁻⁵ 1-4 No. 4 Example Compound 406 5.60 × 10⁴ 451.6 283.3 6.59 ×10⁻⁶ 1-5 No. 5 Example Compound 405 5.52 × 10⁴ 451.4 402.8 6.56 × 10⁻⁶1-6 No. 6 Example Compound 446 6.87 × 10⁴ 526.2 202.7 5.58 × 10⁻⁶ 1-7No. 7 Example Compound 443 6.98 × 10⁴ 485.8 467.6 7.01 × 10⁻⁶ 1-8 No. 8Example Compound 421 1.65 × 10⁴ 556.8 68.0 3.72 × 10⁻⁵ 1-9 No. 9 ExampleCompound 388 1.04 × 10⁴ 548.0 58.1 4.18 × 10⁻⁵ 1-10 No. 11 ExampleCompound 418 5.09 × 10⁴ 495.0 48.9 1.19 × 10⁻⁵ 1-11 No. 55 520.2 48.4Example Compound 420 4.50 × 10⁴ 555 70.3 1.05 × 10⁻⁵ 1-12 No. 56 Comp.Comp. 438 5.07 × 10⁴ 480.4 619.8 6.56 × 10⁻⁶ Example 1-1 Compound No. 1Comp. Comp. 433 5.65 × 10⁴ undetected undetected 5.88 × 10⁻⁶ Example 1-2Compound No. 2 Comp. Comp. 375 7.22 × 10⁴ undetected undetected 6.21 ×10⁻⁶ Example 1-3 Compound No. 3

Examples 2-1 to 2-6 and Comparative Example 2-1

The quantum efficiency of the Schiff base type compounds shown in Table5 and comparative compound 1, all in powder form, was determined using afluorescence spectrophotometer F4500 from Hitachi High-TechnologiesCorp. and a φ60 integrating sphere. Light having a wavelength near theabsorption maximum wavelength (λ_(max)) in a toluene solvent was used asexciting light. The quantum efficiency was calculated from the arearatio. The results are shown in Table 6.

TABLE 6 Schiff Base Compound Quantum Efficiency (%) Example 2-1 CompoundNo. 2 49.9 Example 2-2 Compound No. 3 58.4 Example 2-3 Compound No. 557.6 Example 2-4 Compound No. 6 39.5 Example 2-5 Compound No. 7 11Example 2-6 Compound No. 8 24.4 Comp. Example 2-1 Comp. Compound 1 4.4

It is apparent from Table 6 that the Schiff base type compounds of theinvention emit high fluorescence in their solid state as well.

Examples 3-1 to 3-6 and Comparative Example 3-1

Each of the Schiff base type compounds and comparative compound shown inTable 7 was dissolved in a 20 wt % solution of polymethyl methacrylatein toluene in a concentration showing an absorbance of 0.5 at theλ_(max). The solution was applied to a 100 μm thick polyethyleneterephthalate film with a wire bar RDS30 (from RDS Webster, N.Y.) andheated in an oven at 100° C. for 10 minutes to obtain an optical filter(color conversion filter) of the invention or for comparison. Theabsorption spectrum of the resulting optical filter was determined usinga spectrophotometer U-3010 from Hitachi High-Technologies Corp. Thefluorescence spectrum was then determined using a fluorescencespectrophotometer F4500 from Hitachi High-Technologies Corp. Lighthaving a wavelength of the λ_(max) of each individual filter was used asexciting light. The quantum efficiency of the filter was determinedusing a fluorescence spectrophotometer F4500 from HitachiHigh-Technologies Corp. and a φ60 integrating sphere. Light having awavelength near the λ_(max) of each individual filter was used asexciting light. The quantum efficiency was calculated from the arearatio. The results are shown in Table 7.

TABLE 7 Fluores- cence Quantum Optical Schiff Base EM_(max) Inten-Efficiency Filter Compound λ_(max(nm)) Abs. (nm) sity (%) ExampleCompound 398 0.52 448.2 489.2 56.7 3-1 No. 2 Example Compound 417 0.52542.2 209.9 53.2 3-2 No. 3 Example Compound 408 0.52 455.6 468.9 51.43-3 No. 5 Example Compound 406 0.49 455.4 486.1 57.0 3-4 No. 6 ExampleCompound 446 0.48 521.0 311.0 49.4 3-5 No. 7 Example Compound 443 0.54488.2 395.8 45.2 3-6 No. 8 Comp. Comp. 448 0.58 495.8 519.6 35.1 ExampleCompound 1 3-1

It is apparent from Table 7 that the Schiff base type compounds of theinvention emit high fluorescence in the form of film as well.

Evaluation Examples 1-1 to 1-6 and Comparative Evaluation Example 1-1

The optical filters of the invention obtained in Examples 3-1 to 3-6 andthe comparative optical filter obtained in Comparative Example 3-1 wereevaluated for light resistance (24-hour irradiation) using a xenonWeather-O-Meter Table Sun from Suga Test Instruments Co., Ltd. Thefluorescence intensity of the filter was measured at the emissionmaximum wavelength (EM_(max)) of each individual filter before and after24-hour irradiation. The fluorescence intensity after the irradiationwas relatively expressed with the initial value (before irradiation)taken as 100. The results obtained are shown in Table 8.

TABLE 8 Fluorescence Intensity after Optical Filter 24 hr IrradiationEvaluation Example 1-1 Example 2-1 18 Evaluation Example 1-2 Example 2-234 Evaluation Example 1-3 Example 2-3 35 Evaluation Example 1-4 Example2-4 36 Evaluation Example 1-5 Example 2-5 49 Evaluation Example 1-6Example 2-6 46 Comp. Evaluation Example 1-1 Comp. Example 2-1 10

It is apparent from Table 8 that the optical filter containing acompound structurally different from the compounds of the inventionundergoes great reduction in fluorescence intensity when irradiated withxenon light, whilst the optical filters containing the Schiff base typecompound of the invention are superior in light resistance.

As described, it has been demonstrated that the Schiff base typecompound of the invention emits fluorescence in any of solution, solid,and film forms and that the optical filter (color conversion filter)containing the Schiff base type compound of the invention is excellentin color conversion performance and light resistance and thereforeuseful in color converting light emitting devices and photoelectricdevices.

-   10R: red filter layer-   10G: green filter layer-   10B: blue filter layer-   20R: red color-conversion layer-   20G: green color-conversion layer-   20B: blue color-conversion layer-   30: black mask-   40: light emitting layer-   50: substrate-   100: substrate-   105: optically functional substrate-   110: primer layer-   120: optically functional layer-   130: antireflective layer-   140: hardcoat layer-   150: lubricating layer-   200: topsheet layer-   210: transparent substrate-   220: filler layer-   230: light collecting film-   240: photoelectric element-   250: backsheet layer

The invention claimed is:
 1. A Schiff base type compound represented bygeneral formula (I):

wherein ring A represents an aromatic ring, an aliphatic ring, or aheterocyclic ring; Ar represents a 5- or 6-membered heterocyclic oraromatic ring; and X represents a halogen atom, the aliphatic ringrepresented by ring A and the aromatic ring and the heterocyclic ringrepresented by ring A or Ar being optionally fused to a ring oroptionally substituted, at least one of the hydrogen atoms bonded toring A or Ar being displaced by an amino group represented by —NR″R′″,wherein R″ and R′″ each represent an alkyl group having 1 to 10 carbonatoms or an aryl group having 6 to 10 carbon atoms and may be each takentogether with ring A or Ar to form a ring structure.
 2. The Schiff basetype compound according to claim 1, being represented by general formula(II):

wherein, R¹, R², R³, and R⁴ each independently represent a hydrogenatom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, acarboxyl group, —NR″R′″, an optionally substituted alkyl group having 1to 20 carbon atoms, an optionally substituted aryl group having 6 to 20carbon atoms, an optionally substituted heterocyclic ring having 4 to 20carbon atoms, or an optionally substituted arylalkyl group having 7 to20 carbon atoms; or adjacent two of R¹, R², R³, and R⁴ are takentogether to form an aliphatic, aromatic, or heterocyclic ring, amethylene chain of the alkyl group or of the arylalkyl group and thebond between the aryl group and the benzene ring being optionallyinterrupted by —O—, —S—, —SO₂—, —CO—, —OCO—, or —COO—; and R″ and R′″each represent an alkyl group having 1 to 10 carbon atoms or an arylgroup having 6 to 10 carbon atoms; or R″ and R′″ are taken together withthe adjacent R¹, R², R³, and R⁴, or Ar to form a ring structure; Ar andX are as defined for general formula (I), at least one of the hydrogenatoms bonded to R¹, R², R³, and R⁴, or Ar being displaced by an aminogroup represented by —NR″R′″.
 3. The Schiff base type compound accordingto claim 2, being represented by general formula (III):


4. A color conversion layer comprising a coloring material comprisingthe at least one Schiff base type compound according to claim
 3. 5. Acolor conversion filter comprising one or more color conversion layers,at least one of which is the color conversion layer according to claim4.
 6. A light absorbing layer comprising a coloring material comprisingthe at least one Schiff base type compound according to claim
 3. 7. Alight absorbing filter comprising one or more light absorbing layers, atleast one of which is the light absorbing layer according to claim
 6. 8.A color conversion layer comprising a coloring material comprising theat least one Schiff base type compound according to claim
 2. 9. A colorconversion filter comprising one or more color conversion layers, atleast one of which is the color conversion layer according to claim 8.10. A light absorbing layer comprising a coloring material comprisingthe at least one Schiff base type compound according to claim
 2. 11. Alight absorbing filter comprising one or more light absorbing layers, atleast one of which is the light absorbing layer according to claim 10.12. A color conversion layer comprising a coloring material comprisingthe at least one Schiff base type compound according to claim
 1. 13. Acolor conversion filter comprising one or more color conversion layers,at least one of which is the color conversion layer according to claim12.
 14. A photoelectric device comprising a photoelectric element andthe color conversion filter according to claim
 13. 15. A light absorbinglayer comprising a coloring material comprising the at least one Schiffbase type compound according to claim
 1. 16. A light absorbing filtercomprising one or more light absorbing layers, at least one of which isthe light absorbing layer according to claim
 15. 17. A color-converting,light-emitting device comprising: a light emitting portion and a colorconversion layer comprising a coloring material comprising the at leastone Schiff base type compound according to claim 1; and a colorconversion filter comprising one or more color conversion layers, atleast one of said conversion layers comprising a coloring materialcomprising the at least one Schiff base type compound.
 18. The Schiffbase type compound according to claim 1, selected from the groupconsisting of:


19. A color conversion filter comprising one or more color conversionlayers, at least one of said color conversion layers comprising acoloring material comprising at least one Schiff base type compoundaccording to claim
 18. 20. A color-converting, light-emitting devicecomprising: a light emitting portion and a color conversion layercomprising a coloring material comprising at least one Schiff base typecompound according to claim 18; and a color conversion filter comprisingone or more color conversion layers, at least one of said conversionlayers comprising a coloring material comprising the at least one Schiffbase type compound.